Following the territorial defeat of Islamic State in 2019, western assistance has helped northeastern Syria emerge as a zone of relative stability in the country’s deadlocked civil war. The West’s partner in the fight against Daesh, the Kurdish-led Syrian Democratic Forces (SDF), has been able to establish a de facto statelet covering almost a third of Syria’s territory with a population of approximately four million people. The stability that has been achieved is fragile, however, and contingent on the continued presence of US-led forces.

This paper examines why western support to northeastern Syria has been successful in enabling short-term stability but has struggled to lay the foundations for longer-term peace. It explores how the interaction between external interventions and local actor interests, incentives, and perceptions can shape and constrain the prospects for a sustainable end to violence.